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Capital Stock, Dividends and Common Stock Repurchase Program - Repurchase Program (Detail) $ / shares in Units, shares in Thousands, $ in Millions	1 Months Ended		2 Months Ended	12 Months Ended
	Feb. 08, 2019 USD ($) shares	Nov. 30, 2016 USD ($) shares	Feb. 14, 2019 USD ($)	Dec. 31, 2018 USD ($) item $ / shares shares	Dec. 31, 2017 USD ($) item $ / shares shares	Dec. 31, 2016 USD ($) item $ / shares shares
Accelerated Share Repurchases [Line Items]
Shares repurchased | shares				11,673	10,058	11,241
Weighted average per share purchase price | $ / shares				$ 86.35	$ 77.67	$ 60.49
Total repurchases				$ 1,008	$ 750	$ 725
Cash paid for repurchase of common stock				1,004	750	$ 725
Authorized share repurchases				$ 1,500	$ 1,250
Accelerated Share Repurchase Agreement (ASR) [Member]
Accelerated Share Repurchases [Line Items]
Shares repurchased | shares		400		9,800		3,200
Weighted average per share purchase price | $ / shares						$ 69.43
Total repurchases		$ 225
Number of ASR agreements | item				4	2	4
Cash paid for repurchase of common stock				$ 850	$ 750	$ 725
10b5-1 Plan [Member]
Accelerated Share Repurchases [Line Items]
Shares repurchased | shares	600			1,900
Total repurchases	$ 54			$ 158
Cash paid for repurchase of common stock			$ 4

X

- Definition

Final price paid per share for the purchase of the targeted number of shares, determined by an average market price over a fixed period of time.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 25
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6405686&loc=d3e22802-112653

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The cash outflow to reacquire common stock during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
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Amount of stock repurchase plan authorized.

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Number of shares that have been repurchased during the period and are being held in treasury.

+ References

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-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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The number of accelerated stock repurchase agreements.

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